Propeller for boats and ships



June 2, 1942. H. G. FERGUS PROPELLER FOR BOATS AND SHIPS Filed Dec. 12,1938 Erase G] Ira/3:771 02 z v f FZZQE/T Patented June 2, 1942 I UNITEDSTATES PATENT. OFFICE PROPELLER Fdjt i o iils AND SHIPS ApplicationDecember 12, 1938, Serial No. 245,325

I 6 Claims.

This invention relates to boat propulsion and to means for increasingthe efficiency of the propulsion and increasing the speed and moreparticularly'to an especially designed hull and propeller for effectingthese.

One object of the invention is to provide an improved hull constructionand propeller location whereby the after part of the boat is raised byits own propeller wave and the boat is caused to ride down-hill on itsown stern wave, thereby increasing the speed and decreasing the powerrequired.

Other objects of the invention are to provide center of gravity bydeliberately installing in the midship position in' the keel anespecially designed propeller, thereby causing the center of gravity ormass load to be thrown in the same direction that the boat is traveling.

Additional objects of the invention are to effect simplicity andeificiency in such constructions an improved propeller cooperating withan improved hull construction for still further increasing the speed andefficiency, and to provide a boat and propeller that may be driven withefiiciency in either direction, and to provide a propeller that avoidscavitation.

Features of the invention are- 1 I First, an especially designed hullforfacilitating the propulsion and an especially designed propellercooperating with the hull to increase the re-action from the projectionof water sternward by the propeller, so as to take advantage in a greatdegree of the increased thrust a boat derives from the frictional wakeor zone of water following in the direction of the boat. J

Second, to give to the boat or ship a reduced gravitational downwardpull by raising the stern of the boat or ship so that the mass load ortonnage is in a down hill position. I

Third, to allow the propeller to reduce'its slippage as it increases itsspeed and the ship'increases its momentum or speed. 1

Fourth, to provide for driving the'boat or ship in either direction bythe same propeller, byreversing its direction of rotation, in which casethe boat can be provided with rudders at both ends, which may be workedin unison. I

Fifth, to provide an improved propeller positioned so that the resultingwave sternward raises the rear of the boat orship so as to throw itsmass tonnage forward of the normal center of gravity, taking advantageof the downhill position the boat or ship assumes.

Any vessel'designed so to float on the water by its displacement,depends for its motive power to propel it on such unit of power as isinstalled in or on the boat insuch a fashion as to cause its propellerto contact the Water'and by a'rotating or revolving of its propeller,moves the boat in a directed course, and creates a center'of gravitycontrary to its normal center of gravity when in an idle floatingposition. I utilize this changing and to provide an extremely simpleconstruction which is economical, and reliable in operation, andeconomical to build.

Still other objects of the invention will appear as the descriptionproceeds; and while herein details of the invention are described in thespecification and some of the claims, the invention as described in thebroader claims is not limited to these, and many and various changes maybe made without departing from the scope of the invention as claimed inthe broader claims.

The inventive featuresfor the accomplishment of these and other objectsare shown herein in connection with a boat which briefly stated,includes a boat comprising a hull tapering to both ends to form similarbows, and provided at the mid-section of the bottom with a downwardlyopen bubble pocket in which is longitudinally mounted an axiallyelongated propeller constructed and positioned to cause water projectedsternward from thepropeller under the hullto raise the stern so that the'loa d'is thrown for- Ward and is in down hill position in the directionof travel to cause downhill riding of the boat thereby to increase thespeed and efliciency of the propulsion.

' In the accompanying drawing showing, by way of example, one of manypossible embodiments of the invention,

Fig. 1 is a side elevation partly in longitudinal vertical section,showing the boat in exaggeratedly inclined down-hill-riding positionwith the center of gravity forward of the mid-section;

Fig. 2 is plan showing the boat at rest;

Fig. 3 is a transverse vertical sectional view of the mid-section of theboat, showing the bubble pocket and propeller therein,. and taken on theline 33 of Fig. 1. i

Fig. 4 is a side elevation of the propeller; and

Fig. 5 is a transverse vertical plane sectional view of the propellertaken substantially on the line 5-5 of Fig. 4, lookingin the directionof the arrows of said line. I

My improved boat comprises a hull I!) havingapproximately vertical sidesI l outwardly rounded between the top and bottom thereof and wide at itsmid-section l2 and tapering to both ends to form identical medium sharpinwardly and downwardly inclined bows merging into the boat bottom I4,said bottom being provided at the mid-section with a longitudinallyelongated concaved face portion forming a deep downwardly open bubblepocket I5 having at its sides downwardly projected convexedly roundedlongitudinal bulbs I6, I6 forming closed sides of the pocket and mergingat their sides and ends respectively with the sides II and bottom I4 ofthe hull.

Said bubble pocket I5 is deepest at the midpart and has its forward andaft parts I8 of its face inclined downwardly and merging with the hullbottom I4 to form inclined reaction surfaces I8 each extending from thepropeller more than a quarter of the length of the submerged' portion ofthe hull, said bottom having a substantially fiat reaction part I4 justbeyond each end of the pocket. A helical propeller 20 is axiallylongitudinally disposed in the mid-part of said pocket as will beexplained.

The bulbs I6 form closed pocket sides of the pocket serving as a guidemeans to guide and direct rearwardly from the propeller inward of thesides of the hull and sternward under said inclined reaction surface I8and flat part I4 any water that may move laterally from the propeller.

The inclined reaction surface I8 and flat part I4 together extendlongitudinally of the hull a distance more than half of the submergedlength of that portion of the hull forward of the pocket, said distancebeing great enough in relation to the length of the said portion and thehull to cause the pressure on said reaction surface and flat part by thewater directed thereto by the propeller and said closed sides at thebulbs I6 to appreciably raise the stern part of the hull. The propeller,said closed sides, the weight of said portion, the reaction of the wateron said surfaceand part in said relation cooperating to raise the sternpart of the hull a useful amount and to raise it enough and tilt thehull forwardly downwardly enough to throw the load forwardly enough indown hill position in the direction of travel to appreciably increasethe forward thrust on the hull, thereby increasing the speed andreducing the power required to propel the boat.

The design of the hullcauses the bubble pocket above the propeller toassist in its buoyancy. The design of the hull contributes to itssteadiness and stabilization thereby increasing its safety.

As shown, the propeller comprises two helical blades 25 diminished ateach end, each blade having approximately two complete half turns, thepitch of the blades approximating twice the diameter of the propeller.

The propeller blades are fast on a large elongated cylindrical hub 21,the diameter of the hub being greater than the radial length of eachblade, thereb retaining only the more efficient part of the blades anddiverting the flow of water to said face I8 and part I4. The radii ofboth faces 28, 29 of both blades are straight and radial to the axis ofthe propeller, whereby the thickness of each blade at itsperipheral partis approximately twice the thickness of the blade at the hub, wherebycavitation is greatly reduced when the propeller is driven in eitherdirection, whereby the boat may be driven in either direction with greatefficiency, and whereby the water is thrust straight to the rear of thepropeller against the axis of the reaction surface I8 and said reactionpart I4, thereby to increase the lifting action of the water on theafter part of the hull.

The especially designed hull cooperates with the propeller to cause theboat or ship to ride on the wave caused by the propeller, therebychanging the center of gravity of the boat from the normal idle positionto the position as shown in Fig 1. The invention is not limited to asingle propeller to accomplish the same result. The pitch of thepropeller and the lines of the keel or hull are coordinated best toaccomplish the desired effect.

The thrust-producing power loss that is termed cavitation is reduced bymy especially designed propeller, in that the cavity ordinarily producedat the back of the blades of a propeller from its pitch, is reduced to aminimum by constructing the propeller blades so that the radii of bothside faces are straight and radial to the axis of the propeller. Theblades of the propeller diminish at both ends to the hub as shown inFig. 4.

The aforementioned improvement in propelling boats or ships may be usedindividually or collectively in such a manner as to use the basicprinciples described therein whether in part or in full if employed inboats or ships or not,

I provide an especially designed keel 3B which allows the installationof the propeller 28 to be placed and revolved in the exact midshipsection so as to cause the changing of the center of gravity from normalto downhill. Th'e keel 38 is disposed in the axial vertical plane of thehull and has a continuous approximately straight lower edge and upwardlyoutwardly inclined ends 3| extending as high as, and slightly below thehull and beyond the ends of the hull. Said keel at the bubble pocket isshown as having a longitudinal cut-out 3| in which the elongated helicalpropeller 28 is longitudinally disposed and protected, the propellershaft being mounted in bearings at both ends of the cut-out and extendedto and driven by a suitable engine or motor 32 within the hull.

Each end of the keel is shown as being provided' with an end cut-out 34in which are mounted rudders 35 respectively, which may be operated insynchronism or independently.

The propeller and its shaft are so positioned that the ship cradles fromthe center, thereby allowing the horizontal idle position of the boat tobe changed when its propeller revolves to shift the mass load forward oraft as the case may be depending upon the direction of rotation. Asshown in Fig. 1, the boat is being propelled in the direction of thearrow A and is forwardly and downwardly inclined relative to the waterline L.

The invention claimed is:

1. A boat comprising a hull having its sides tapering from itsmid-section to both ends to form identical stems; said bottom beingprovided at the mid-section with a downwardly opening bubble pocket,deepest at its mid-part and having its face downwardly inclined at bothends and merging with the bottom; and a helical propeller axiallylongitudinally disposed in said pocket and adapted to propel equallywell in either direction, whereby said boat may be propelled equallywell in either direction with a single propeller.

2. A boat comprising a hull provided near the mid-section of its bottomwith a longitudinally elongated downwardly opening upwardly extendedbubble pocket closed at each side; a helical propeller axiallylongitudinally disposed in the mid-part of said pocket; said bubblepocket having the aft parts of its face inclined down- Wdldly andmerging with the bottom to form the propeller more than a quarter of thelength of the submerged portion of the hull; said hull having asubstantially flat reaction part just beyond the rear of the pocket; theclosed pocket sides serving as a guide means 'to guide and direct,inward of the sides of the hull and sternward under said inclinedreaction surface and flat part, water that may be caused to movelaterally in the pocket, thereby to raise the stern.

3. In a boat as in claim 2, said inclined reaction surface and flat parttogether extending longitudinally of the hull a distance more than halfof the submerged length of that portion of the hull forward of thepocket, said distance being great enough in relation to the length ofthe said portion and the hull to cause the pressure on said reactionsurface and flat part by the water directed thereto by the propeller andsaid closed sides to appreciably raise the stern part of the hull; thepropeller, said guide means, the weight of said portion, the reaction ofthe water on said surface and part in said relation cooperating to raisethe stern part of the hull a useful amount and to raise it enough andtilt the hull forwardly downwardly enough to throw the load forwardlyenough in down hill position in the direction of travel to appreciablyincrease the forward thrust on the hull, thereby appreciably increasingthe speed and appreciably reducing the power required to propel theboat.

4. In a boat as in claim 2, the blades of said propeller being sodesigned that nearly all of the water is thrust straight to the rear ofthe propeller against the axis of the reaction surface and said reactionpart, thereby to increase the lifting action of the water on the afterpart of the hull; said inclined reaction surface and flat part togetherextending longitudinally of the hull a distance greater than half of thesubmerged length of that portion of the hull forward of the pocket, andgreater than half the submerged length of the hull, said distance beinggreat enough in relation to the length of the said portion and the hullto cause the pressure on said reaction surface and fiat part by thewater directed thereto by the propeller and said closed sides to raisethe stern part of the hull; the propeller, its straight rearward thrust,said guide means, the weight of said portion, the reaction of the wateron said surface and reaction part in said relation cooperating togreatly raise the stern part of the hull and to raise it enough andincline the hull forwardly downwardly enough to throw the load forwardlyenough in down hill position in the direction of travel to greatlyincrease the forward thrust on the hull, thereby increasing the speedand reducing the power required to propel the boat.

,5. In a boat as in claim 2, said propeller comprising a large elongatedcylindrical hub, and two helical blades joining the hub; the radii ofboth faces of both blades being straight and radial to the axis of thepropeller, whereby the thickness of each blade at its peripheral part ismore than twice the thickness of the blade at the hub whereby cavitationis greatly reduced, and

whereby the water is thrust straight to the rear of the propelleragainst the axis of the reaction lllllll llfl ill Willi it n to creasethe lifting action of the water on the after part of the hull; saidinclined reaction surface and flat part together extendinglongitudinally of the hull a distance more than half of the submergedlength of that portionof the hull forward of the pocket; the propeller,its straight rearward thrust, said guide means, the weight of saidportion, the reaction of the water on said surface and reaction part insaid relation cooperating to raise greatly the stern part of the hulland to raise it enough and incline the hull forwardly downwardly enoughto throw the load forwardly enough in down hill position in thedirection of travel to greatly increase the forward thrust on the hull,thereby increasing the speed and reducing the power required to propelthe boat.

6. A boat comprising a hull provided at the mid-section of its bottomwith a longitudinally elongated downwardly opening upwardly extendedbubble pocket closed at each side; a helical propeller, adapted topropel in either direction, axially longitudinally disposed in themid-part of said pocket; said bubble pocket having the forward and aftparts of its face inclined downwardly and merging with the bottom toform inclined reaction surfaces each extending from the propeller morethan a quarter of the length of the submerged portion of the hull; saidhull having a substantially flat reaction part just beyond each end ofthe pocket; the closed pocket sides serving as a guide means to guideand direct the water projected sternward from the propeller inward ofthe sides of the hull and sternward under said inclined reaction surfaceand fiat part thereby to raise the stern; said propeller comprising alarge elongated cylindrical hub, and two helical blades joining the hub;the diameter of the hub being greater than the radial length of eachblade, thereby retaining only the more efficient part and diverting theflow of water to said part; the radii of both faces of both blades beingstraight and radial to the axis of the propeller, whereby the thicknessof each blade at its peripheral part is more than twice the thickness ofthe blade at the hub whereby cavitation is greatly reduced when thepropeller is driven in either direction with great efliciency by asingle propeller; and whereby the water is thrust straight to the rearof the propeller; each of said inclined reaction surfaces and associatedflat part together extending longitudinally of the hull a distance morethan half of the submerged length of that portion of the hull forward ofthe pocket, said distance being great enough in relation to the lengthof the said portion and the hull to cause the pressure on said reactionsurface and fiat reaction part by the water directed thereto by thepropeller and said closed sides to raise the stern part of the hull; thepropeller, its straight thrust, said guide means, said portion, thereaction of the water on said surface and part in said relationcooperating to raise greatly the stern part of the hull, when the boatis propelled in either direction.

HORACE G. FERGUS.

